The subject matter disclosed herein relates to a heat shield for a transition piece aft frame assembly.
Gas turbines generally include a compressor, a combustor, one or more fuel nozzles, and a turbine. Air enters the gas turbine through an air intake and is compressed by the compressor. The compressed air is then mixed with fuel supplied by the fuel nozzles. The air-fuel mixture is supplied to the combustor at a specified ratio for combustion. The combustion generates pressurized exhaust gases, which drive blades of the turbine.
The combustor includes a transition piece for confining and directing flow of combustion products from the combustor to a first stage nozzle. The transition piece includes a forward end and an aft end. Located between the aft end of the transition piece and the first stage nozzle is a transition piece aft frame. Exhaust gas flows through the transition piece at relatively high temperatures, therefore cracking due to thermal stresses and oxidation may occur in the transition piece aft frame along the inner and outer rails. To reduce the temperature of the transition piece aft frame, cooling holes or apertures may be provided in the transition piece aft frame. There are also various types of seal designs that are currently available to substantially prevent leaking of cooling air provided by the cooling apertures. However, there is no feature currently available to substantially prevent exhaust gases from reaching the transition piece aft frame in the region where cracking and oxidation may occur.